Home networking is evolving into an environment in which people will be sharing photographs, music, video, data and voice among networked consumer electronics, personal computers and mobile devices throughout the home. Consumers will be able to stream video content from a personal computer or electronic device to flat panel high-definition television (HDTV) without the use of wires. A technology that will be implemented for enabling these capabilities is ultra wideband (UWB). UWB is a wireless technology designed for short-range, personal area networks.
The Federal Communications Committee (FCC) has mandated that UWB radio transmission can legally operate in the frequency range of 3.1 GHz to 10.6 GHz, at a transmission power of −41.25 dBm/MHz, having a minimum bandwidth of 500 MHz. Basically, UWB devices provide wide bandwidth transmission at very low signal power levels. Due to the low transmission signal power levels of UWB, transmission interference can be a very big issue. The interference can be from both non-UWB devices, and similar UWB devices.
FIG. 1 shows an example of an indoor broad band wireless communication network 100. The network 100 includes a high definition television (HDTV) monitor 110 networked with other devices, such as, a digital video recorder (DVR) 120, a digital video disk (DVD) player 140 and a computing device 130.
HDTV streaming video requires large bandwidths of information. Therefore, the networking of devices that include streaming HDTV must be capable of handling high bandwidths. Additionally, the devices of the network must be resistance to both self-interference and interference from other wireless communication signals. UWB wireless signals operate at very low power levels, making resistance to interference more difficult.
Personal home networks operating at very high data bandwidths can suffer from multi-path, which can constructively or destructively add to the main (typically, the shortest) transmission path. The multi-path signals are delayed copies of the signal of the main path multiplied by a random phase and amplitude, and cause inter-symbol interference (ISI). That is, an echo of a previously transmitted symbol can interfere with the reception of a present symbol.
To alleviate the effects of ISI, an implementation of UWB includes orthogonal frequency division multiplexing (OFDM) signal transmission. OFDM is a special form of multi-carrier modulation in which multiple user symbols are transmitted in parallel using different sub-carriers. The sub-carriers have overlapping frequency spectra, but their signal waveforms are specifically chosen to be orthogonal. OFDM systems transmit symbols that have substantially longer time durations than the length of the impulse response of the transmission channel, thereby allowing avoidance of ISI. OFDM modulation techniques are very efficient in indoor broad band wireless communication. However, even OFDM signals suffer when in the presence of interfering devices.
It is desirable to have an apparatus and method for a wireless data transmission in which lower power devices can communicate without interference from like devices inhibiting the wireless data transmission, and are resistant to interference from unlike devices as well.